I doubt that powdercoating would be a good option for revolvers. It has thickness and between the powdercoating on the cylinder and topstrap it might not cycle.
I had my shotgun powdercoated. They didn't tape it off very well and got some overspray inside the receiver, and too far down the barrel so that it would not go into the receiver until after painstakingly sanding it off of there.
That's it. Other than that PC'ing a gun makes it weatherproof. It almost made the serial number go away also. Careful with that.